RESUMEN
Poor nutrition of women during pregnancy causes reduction in foetal growth and can adversely affect the development of the foetal lungs. The purpose of the present study was to assess the effects of maternal protein restriction on the postnatal lung development in neonatal period, and on lung structure in adult rat offspring. Female virgin Sprague-Dawley albino rats (more than 200 g) were used. One male rat was introduced into a cage with one female for matting. Once the pregnancy was confirmed, pregnant rats were divided into two main groups; each consists of 6 female as follow: 1 - normally nourished group; 2 - protein deficient group. After delivery, offspring were subdivided into three groups: 1 day after delivery, 2 weeks and 2 months postnatal. Rat body and lung weight were recorded and ratio of lung weight to body weight was assessed. Total plasma protein and serum albumin were assessed for all groups. Lung tissue stained with H&E for histological and morphometric analysis. Immunohistochemistry was performed to evaluate the number of cells positive for pulmonary surfactant protein A. Our results showed that protein restriction interfere with neonatal and postnatal lung development resulting in morphological and morphometric changes of normal lung development. We concluded that protein deficiency lead to developmental retardation of lung.
RESUMEN
Isolated purified contractile tail sheaths of bacteriophage T2L were analyzed for their carboxyl terminal amino acids by carboxypeptidase treatment and hydrazinolysis. Glycine and serine were identified as the only two carboxyl end groups. Using corrections for the yields of these two amino acids upon hydrazinolysis, we calculated that there are 154 (+/-30) moles of C-terminal glycine and 130 (+/-45) moles of C-terminal serine per mole of sheath. It appears likely that sheaths contain two types of polypeptide chains in equal numbers, probably 144 of each. The relation of these two components to the mechanism of sheath contraction is discussed.